isosorbide dinitrate and hydralazine hydrochloride

1 INDICATIONS AND USAGE Isosorbide dinitrate and hydralazine hydrochloride tablets are a combination of isosorbide dinitrate, a nitrate vasodilator, and hydralazine hydrochloride, an arteriolar vasodilator, indicated for: the treatment of heart failure as an adjunct therapy to standard therapy in self-identified black patients to improve survival, prolong time to hospitalization for heart failure and to improve patient-reported functional status ( 1.1 ) Limitations of use: There is little experience in patients with NYHA class IV heart failure ( 1.2 ) 1.1 Treatment of Heart Failure in Self-identified Black Patients Isosorbide dinitrate and hydralazine hydrochloride tablets are indicated for the treatment of heart failure as an adjunct to standard therapy in self-identified black patients to improve survival, to prolong time to hospitalization for heart failure, and to improve patient-reported functional status. 1.2 Limitations of Use There is little experience in patients with NYHA class IV heart failure.

2 DOSAGE AND ADMINISTRATION Isosorbide dinitrate and hydralazine hydrochloride tablets should be initiated at a dose of one isosorbide dinitrate and hydralazine hydrochloride tablet, three times a day. Titrate to a maximum of two tablets three times daily, if tolerated. Although titration of isosorbide dinitrate and hydralazine hydrochloride tablets can be rapid (3-5 days), some patients may experience side effects and may take longer to reach their maximum tolerated dose. The dosage may be decreased to as little as one-half isosorbide dinitrate and hydralazine hydrochloride tablet three times a day if intolerable side effects occur. Efforts should be made to titrate up as soon as side effects subside. One tablet three times a day titrated to a maximum tolerated dose up to two tablets three times a day ( 2 ) Dosage may be decreased to as little as one-half tablet three times a day if intolerable side effects occur. Efforts should be made to titrate up as soon as side effects subside ( 2 )

3 DOSAGE FORMS AND STRENGTHS The isosorbide dinitrate and hydralazine hydrochloride tablets (20 mg isosorbide dinitrate and 37.5 mg hydralazine hydrochloride) are orange, biconvex, approximately 8 mm in diameter, scored, film-coated, and debossed with "20" on one side over the score and " N " on the other side. Tablets (scored): 20 mg isosorbide dinitrate and 37.5 mg hydralazine hydrochloride ( 3 )

4 CONTRAINDICATIONS Isosorbide dinitrate and hydralazine hydrochloride tablets are contraindicated in patients who are allergic to organic nitrates. Do not use isosorbide dinitrate and hydralazine hydrochloride tablets in patients who are taking PDE-5 inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil. Concomitant use can cause severe hypotension, syncope, or myocardial ischemia [see Drug Interactions (7.1) ] . Do not use isosorbide dinitrate and hydralazine hydrochloride tablets in patients who are taking the soluble guanylate cyclase (sGC) stimulator riociguat. Concomitant use can cause hypotension. Patients who are allergic to organic nitrates ( 4 ) Use of phosphodiesterase type 5 (PDE5) inhibitors, such as avanafil, sildenafil, tadalafil, or vardenafil, or soluble guanylate cyclase (sGC) stimulator (riociguat). ( 4 )

6 ADVERSE REACTIONS Most common adverse reactions (≥ 5% more on isosorbide dinitrate and hydralazine hydrochloride tablets than on placebo) were headache and dizziness ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Wilshire Pharmaceuticals, Inc. at 1-877-495-6856 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. Isosorbide dinitrate and hydralazine hydrochloride tablets have been evaluated for safety in 517 heart failure patients in A-HeFT. A total of 317 of these patients received isosorbide dinitrate and hydralazine hydrochloride tablets for at least 6 months, and 220 received isosorbide dinitrate and hydralazine hydrochloride tablets for at least 12 months. In A-HeFT, 21% of the patients discontinued isosorbide dinitrate and hydralazine hydrochloride tablets for adverse reactions compared to 12% who discontinued placebo. Overall, adverse reactions were more common in isosorbide dinitrate and hydralazine hydrochloride tablets-treated than in placebo-treated patients. Table 1 lists adverse reactions reported with an incidence, after rounding, ≥ 2% higher on isosorbide dinitrate and hydralazine hydrochloride tablets than on placebo in A-HeFT, regardless of causality. The most common reasons for discontinuing isosorbide dinitrate and hydralazine hydrochloride tablets in the A-HeFT trial was headache (7%). Table 1. Adverse Reactions Occurring in the A-HeFT Study in ≥ 2% of Patients Treated with isosorbide dinitrate and hydralazine hydrochloride tablets. Isosorbide dinitrate and hydralazine hydrochloride tablets (N=517) % Placebo (N=527) % Headache 50 21 Dizziness 32 14 Asthenia 14 11 Nausea 10 6 Hypotension 8 4 Sinusitis 4 2 Ventricular tachycardia 4 2 Paresthesia 4 2 Vomiting 4 2 Amblyopia 3 1 In the V-HeFT I and II clinical studies, a total of 587 patients with heart failure were treated with the combination of isosorbide dinitrate and hydralazine hydrochloride. The type, pattern, frequency and severity of adverse reactions reported in these studies were similar to those reported in A-HeFT, described above and no unusual adverse reactions were reported. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of isosorbide dinitrate and hydralazine hydrochloride tablets . Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Use of Isosorbide dinitrate and hydralazine hydrochloride tablets: The following adverse reactions have been identified with use of isosorbide dinitrate and hydralazine hydrochloride tablets. Cardiac Disorders: Palpitations Ear and labyrinth disorders: Tinnitus, vertigo Eye Disorders: Eyelid edema, vision blurred Gastrointestinal Disorders: Abdominal discomfort, constipation General Disorders and Administration Site Conditions: Facial pain, flushing, chest discomfort, chest pain, peripheral edema Musculoskeletal and Connective Tissue Disorders: Pain in extremity, myalgia Nervous Disorders: Dysgeusia, hypoaesthesia, migraine, syncope Renal and Urinary Disorders: Chromaturia, pulmonary renal syndrome Respiratory, Thoracic and Mediastinal Disorders: Dyspnea Reproductive System and Breast Disorders: Erectile dysfunction Skin and Subcutaneous Tissue Disorders: Erythema, hyperhidrosis, pruritus, face swelling Use of Hydralazine Hydrochloride or Isosorbide Dinitrate: The following reactions have been reported with use of either hydralazine hydrochloride or isosorbide dinitrate. Blood and Lymphatic System Disorders: Blood dyscrasias, agranulocytosis, purpura, eosinophilia, splenomegaly. Eye Disorders: Lacrimation, conju …

7 DRUG INTERACTIONS 7.1 Phosphodiesterase Inhibitors Isosorbide dinitrate and hydralazine hydrochloride tablets are contraindicated in patients who are using a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), PDE5 inhibitors such as avanafil, sildenafil, vardenafil, and tadalafil have been shown to potentiate the hypotensive effects of organic nitrates. Do not use isosorbide dinitrate and hydralazine hydrochloride tablets in patients who are taking the soluble guanylate cyclase (sGC) stimulator riociguat. Concomitant use can cause hypotension [see Contraindications (4) ] .

8 USE IN SPECIFIC POPULATIONS Geriatric Use: Isosorbide dinitrate and hydralazine may be eliminated more slowly in elderly patients. Initiate therapy at the low end of the dosing range ( 8.5 ) 8.1 Pregnancy Risk Summary There are no data on isosorbide dinitrate and hydralazine hydrochloride tablets use in pregnant women, and insufficient data on its components (hydralazine and isosorbide dinitrate) to assess a drug-associated risk of major birth defects or miscarriage with first trimester use. Available published data on hydralazine use in pregnancy during the second and third trimesters have not shown an association with adverse pregnancy-related outcomes. Hydralazine hydrochloride is teratogenic in mice at 66 mg/kg and possibly in rabbits at 33 mg/kg (2 and 3 times the MRHD of isosorbide dinitrate and hydralazine hydrochloride tablets on a body surface area basis). Isosorbide dinitrate has been shown to cause a dose-related increase in embryo-toxicity (excess mummified pups) in rabbits at 70 mg/kg (12 times the MRHD of isosorbide dinitrate and hydralazine hydrochloride tablets on a body surface area basis). All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Clinical Considerations Disease-Associated Maternal and/or Embryo/Fetal Risk Pregnant women with heart failure are at increased risk for preterm birth. Clinical classification of heart disease may worsen with pregnancy and lead to maternal death and/or stillbirth. 8.2 Lactation Risk Summary There are no data on the presence of isosorbide dinitrate and hydralazine hydrochloride tablets in human or animal milk, the effects on the breastfed infant or on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for isosorbide dinitrate and hydralazine hydrochloride tablets and any potential adverse effects on the breastfed child from isosorbide dinitrate and hydralazine hydrochloride tablets or from the underlying maternal condition. 8.4 Pediatric Use The safety and effectiveness of isosorbide dinitrate and hydralazine hydrochloride tablets in children have not been established. 8.5 Geriatric Use Clinical studies of isosorbide dinitrate and hydralazine hydrochloride tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in response between elderly and younger patients. In general, dose selection for an elderly patient should start at the low end of the dosing range, reflecting the greater frequency of decreased hepatic and renal function, and of concomitant disease or other drug therapies. Isosorbide dinitrate, its active metabolites, and hydralazine may be eliminated more slowly in elderly patients. 8.6 Renal Impairment There are no studies of renal impairment using isosorbide dinitrate and hydralazine hydrochloride tablets. No dose adjustment is required for hydralazine or isosorbide dinitrite [see Clinical Pharmacology (12.3) ] . Dialyzability of hydralazine has not been determined . Dialysis is not an effective method for removing isosorbide dinitrate or its metabolite isosorbide-5-mononitrate from the body. 8.7 Hepatic Impairment The effect of hepatic impairment on the pharmacokinetics of hydralazine alone has not been determined. Isosorbide dinitrate concentrations increase in patients with cirrhosis. There are no studies of hepatic impairment using isosorbide dinitrate and hydralazine hydrochloride tablets.

12.1 Mechanism of Action The mechanism of action underlying the beneficial effects of isosorbide dinitrate and hydralazine hydrochloride tablets in the treatment of heart failure has not been established. Isosorbide dinitrate is a vasodilator affecting both arteries and veins. Its dilator properties result from the release of nitric oxide and the subsequent activation of guanylyl cyclase, and ultimate relaxation of vascular smooth muscle. Several well-controlled clinical trials have used exercise testing to assess the anti-anginal efficacy of chronically-delivered nitrates. In the large majority of these trials, active agents were no more effective than placebo after 24 hours (or less) of continuous therapy. Attempts to overcome nitrate tolerance by dose escalation, even to doses far in excess of those used acutely, have consistently failed. Only after nitrates have been absent from the body for several hours is response to nitrates restored. Hydralazine hydrochloride is a selective dilator of arterial smooth muscle. Animal data suggests that hydralazine may also mitigate tolerance to nitrates.

11 DESCRIPTION Isosorbide dinitrate and hydralazine hydrochloride tablets are a fixed-dose combination of isosorbide dinitrate, a vasodilator with effects on both arteries and veins, and hydralazine hydrochloride, a predominantly arterial vasodilator. Isosorbide dinitrate is described chemically as 1,4:3,6-dianhydro-D-glucitol dinitrate and its structural formula is: Isosorbide dinitrate is a white to off-white, crystalline powder with the empirical formula C 6 H 8 N 2 O 8 and a molecular weight of 236.14. It is freely soluble in organic solvents such as alcohol, chloroform and ether, but is only sparingly soluble in water. Hydralazine hydrochloride is described chemically as 1-hydrazinophthalazine monohydrochloride, and its structural formula is: Hydralazine hydrochloride is a white to off-white, crystalline powder with the empirical formula C 8 H 8 N 4 ∙HCl and a molecular weight of 196.64. It is soluble in water, slightly soluble in alcohol, and very slightly soluble in ether. Each isosorbide dinitrate and hydralazine hydrochloride tablet for oral administration contains 20 mg of isosorbide dinitrate and 37.5 mg of hydralazine hydrochloride. The inactive ingredients in isosorbide dinitrate and hydralazine hydrochloride tablets include: anhydrous lactose, microcrystalline cellulose, sodium starch glycolate, colloidal silicon dioxide, magnesium stearate, hypromellose, FD&C Yellow No. 6 aluminum lake, polyethylene glycol, titanium dioxide, polysorbate 80. Chemical Structure Chemical Structure

10 OVERDOSAGE The signs and symptoms of overdosage with isosorbide dinitrate and hydralazine hydrochloride tablets are expected to be those of excessive pharmacologic effect, i.e., vasodilatation, reduced cardiac output and hypotension, and signs and symptoms include headache, confusion, tachycardia, and generalized skin flushing. Complications can include myocardial ischemia and subsequent myocardial infarction, cardiac arrhythmia, and profound shock. Syncope, coma and death may ensue without appropriate treatment. Human Experience: There are no documented cases of overdosage with isosorbide dinitrate and hydralazine hydrochloride tablets. No deaths from acute poisoning have been reported. Treatment: There is no specific antidote. Support of the cardiovascular system is of primary importance. Shock should be treated with plasma expanders, vasopressors, and positive inotropic agents. The gastric contents should be evacuated, taking adequate precautions to prevent aspiration. These manipulations have to be carried out after cardiovascular status has been stabilized, since they might precipitate cardiac arrhythmias or increase the depth of shock. In patients with renal disease or congestive heart failure, therapy resulting in central volume expansion is not without hazard. Treatment of isosorbide dinitrate overdose in these patients may be difficult, and invasive monitoring may be required. No data are available to suggest physiological maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of the components of isosorbide dinitrate and hydralazine hydrochloride tablets. Dialysis is not effective in removing circulating isosorbide dinitrate. The dialyzability of hydralazine has not been determined. Methemoglobinemia: Nitrate ions liberated during metabolism of isosorbide dinitrate can oxidize hemoglobin into methemoglobin. There are case reports of significant methemoglobinemia in association with moderate overdoses of organic nitrates. Methemoglobin levels are measurable by most clinical laboratories. Methemoglobinemia could be serious in chronic heart failure patients because of already compromised vascular bed-tissue gas exchange dynamics. Classically, methemoglobinemic blood is described as chocolate brown, without color change on exposure to air. When methemoglobinemia is diagnosed, the treatment of choice is methylene blue, 1 to 2 mg/kg intravenously.

16 HOW SUPPLIED/STORAGE AND HANDLING Isosorbide dinitrate and hydralazine hydrochloride tablets contain 20 mg of isosorbide dinitrate and 37.5 mg of hydralazine hydrochloride. They are biconvex, approximately 8 mm in diameter, scored, film-coated, orange tablets debossed "20" on one side over the score and "N" on the other side. NDC 72162-2343-9: 90 Tablets in a BOTTLE Store at 25°C (77°F), excursions permitted to 15-30°C (59-86°F). [See USP Controlled Room Temperature.] Keep bottles tightly closed. Protect from light. Dispense in a light-resistant, tight container. Repackaged/Relabeled by: Bryant Ranch Prepack, Inc. Burbank, CA 91504